Investments and Derivative Instruments (Details 7) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Commercial Mortgage Loans Credit Quality
Avg. Debt-Service Coverage Ratio	2.35
Commercial [Member]
Commercial Mortgage Loans Credit Quality
Carrying Value	$ 5,707	$ 5,598
Avg. Debt-Service Coverage Ratio	2.35	2.34
Greater than 80% [Member] | Commercial [Member]
Commercial Mortgage Loans Credit Quality
Carrying Value	95	101
Avg. Debt-Service Coverage Ratio	0.96	0.99
65% - 80% [Member] | Commercial [Member]
Commercial Mortgage Loans Credit Quality
Carrying Value	1,047	1,195
Avg. Debt-Service Coverage Ratio	1.90	1.82
Less than 65% [Member] | Commercial [Member]
Commercial Mortgage Loans Credit Quality
Carrying Value	$ 4,565	$ 4,302
Avg. Debt-Service Coverage Ratio	2.49	2.53